Door chain lock



ug- 6, 1968 R. w. wALDo 3,395,556

DOOR CHAIN LOCK Filed March 27, 1967 INVENTOR RUSSELL W M400 WWW ATTORNEYS United States Patent O 3,395,556 DOOR CHAIN LOCK Russell W. Waldo, St. Paul, Minn., assignor to Ideal Security Hardware Corporation, a corporation of Minnesota Filed Mar. 27, 1967, Ser. No. 626,229 4 Claims. (Cl. 70-93) ABSTRACT OF 'THE DISCLOSURE A chain lock for doors, including a housing defining a passage for reception of a looking slide mounted on one end of a chain, the housing further defining a recess for a tumbler lock operated latch bolt, the looking slide being movable into the passage to be engaged by the latch bolt and held thereby against movement out of the passage.

Backgrozmd of the invention This invention is in the nature of an improvement on door chain looks of the type disclosed in U.S. Letters Patent No. 3,161,035 issued to Adamec et al., such chain looks being utilized to releasably hold a door against opening movements beyond an ajar position; and having a key operated lock which may be opened from the outside of the door, when the same is ajar, to permit full opening of the door. The lock is mounted in a housing adapted to be secured to a door frame and having a passage for reception of a looking slide secured to one end of a chain, and a recess substantially normal to and intersecting the passage, and in which is mounted a lock Controlled latch bolt which engages the looking slide to lock the slide in the passage. For ease in casting or molding the housing, the recess extends through and defines an opening in the rear wall of the housing which opening is normally closed by a separate plate-like part which prevents the latch bolt from tilting the looking slide into the opening during movement of the looking slide inwardly of the passage. Further, and as shown in the Odamec et al. patent, above identified, the housing is usually drilled to receive a retaining pin or the like for the tumbler lock, this pin being rather diflioult to extract for removal and replacement of the tumbler lock.

Summary o the invention The present invention provides a housing having a passage for a looking slide and a transverse recess in a manner similar to that of the Adameo et al. patent, the present recess being of a size and Shape to receive both a latch bolt and a tumbler lock retainin g device.

A feature of the present invention resides in the locking slide which includes a longitudinally extending tongue portion which is adapted to move between the latch bolt and the recess opening through the rear wall of the housing to close the opening prior to engagement of the latch bolt by the looking slide. This arrangement eliminates the necessity for a separate olosure plate or the like for said opening, thus substantially reducing manufacturing costs. The eliminaton of a olosure plate and location of a retainer device in the latch bolt reoeiving recess enables one to obtain ready access to the retainer device for movement of the device in a manner to permit the removal of the tumbler lock, when it is desired to replace the same.

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Description o the drawngs Referring to the drawings, in which like references indicate like parts throughout the several views:

FIG. 1 is a fragmentary view in perspective of a door chain lock mechanism produced in accordance with this invention, applied to a door and door frame;

FIG. 2 is a view in top plan of one of the chain fastening means of this invention, some parts being broken away;

FIG.'3 is a view in bottom plan of the fastening means of FIG. 2, a portion of the door chain being shown in transverse section;

FIG. 4 is a longitudinal section taken substantially on the line 4-4 of FIG. 2;

FIG. 5 is a view corresponding to FIG. 4 but showing a different position of some of the parts;

FIGS. 6 and 7 are transverse sections taken on the 'lines 6-6 and 7- 7 respectively of FIG. 4; and

FIG. 8 is a view in perspective of the looking slide of this invention.

A door chain lock mechanism built in acoordance With this invention comprises a plate member 1, a link chain 2, having a coupler element 3 secured to one of its ends, a looking slide 4, secured to the opposite end of the chain 2, and a housing 5. The plate member 1 and housing member 5 comprise fastening means for operatively securing opposite ends of the chain 2 to a door 6 and door frame 7 respectively.

The plate member 1 and housing 5 are preferably made from cast metal, the plate member 1 being in the form of an elongated generally rectangular housing having mounting fianges 8 that are drilled to receive mounting screws or the like 9 by means of which the plate member 1 is rigidly secured to the inner surface of the door 6. The front Wall 10 of the plate member 1 is provided with a longitudinally extending slot 11 terminating at its end remote from the adjacent edge of the door in an enlarged portion 12 for free reception of the coupler element 3. The coupler element 3 is constructed to enter the slot 11 only at the enlarged end 12 thereof and to be moved longitudinally of the slot 11 for its entire length. The plate member 1 and coupler element 3 are disclosed in U.S. Letters Patent No. 3,275,364, issued to Bert A. Quinn, reference being had thereto. In view of this disclosure, and in further view of the fact that the plate member 1 and coupler element 3 do not, in and of themselves, comprise the instant invention, further detailed description thereof is omitted, in the interest of brevity.

The housing 5 is formed to provide a forward body portion 13, laterally spaced side Wall portions 14, and a rear wall portion 15, said body portions 13-15 Cooperating to define a cross-sectionally generally rectangular passage 16 that extends longitudinally through the housing 5. It will be noted that the side and rear walls 14 and 15 are of greater length than the body portion 13 and extend above and below the body portion 13, the rear Wall 15 being formed to provide a pair of longitudinally spaced countersunk openings 17 for reception of mounting screws or the like 18 by means of which the housing 5 is rigidly secured to the door frame 7.

The body portion 13 is formed adjacent its lower end to provide a rearwardly opening recess 19 that transversely intersects the passage 16 and terminates in an opening 20 through the rear Wall 15, the opening 20 being of the same height and width as the recess 19. The forward body portion-13 has a bottom wall 21 which defines the bottom of the recess 19, and a generally U-shaped fiange 22 cooperates with the bottom wall 21 and adjacent wall portions of the body portion 13 to define guideways for a latch bolt 23 that is movable in the recess 19 toward and away from the opening 20 in the rear wall 15.

The body portion 13 of the housing is provided with a bore 24 having an access parallel to the longitudinal dimension of the passage 16 and which communicates with the recess 19, for reception -of a conventional cylinder or tumbler lock 25. The bore 24 is formed to provide an axially extending notch 26 for reception. of the usual tumbler pins 27 associated with the cylinder lock 25, the lock 25 being provided at its upper end with a diametrically enlarged head 28 that rests upon a shoulder 29 in the bore 24. The lock 25 further includes a latch operating pin 30 that is received in an upwardly opening pocket or cavity 31 in the latch bolt 23, the pin 30 being so disposed that rotation of the cylinder of tumbler lock 25 will impart forward movement to the latch bolt 23, in the usual manner. The lock 25 is provided with the usual opening 32 in its upper end for reception of a key, not shown. The lock 25 is further provided at its lower end portion, and normally within the recess 19, with a generally C-shaped retainer element or washer 33 that is transversely slidable in the lock 25 and is biased toward an eccentric relationship with the lock 25 by a pair of coil compression Springs or the like 34, see FIG. 6. The retaining washer 33 normally engages a top Wall surface portion 35 of the recess 19 to prevent upward withdrawal of the lock 25 from the bore 24.

The latch bolt 23 is yieldingly urged in a rearward direction by a coil compression spring 36, and is formed to provide a beveled rear end 37 that is normally disposed in the passage 16 in forwardly spaced relation to the opening 20 in the rear wall 15. Rotation of the lock 25 will impart forward movement to the latch bolt 23 against bias of the spring 36 to move the beveled end 37 out of the passage 16, the latch bolt 23 being formed to provide a pair of opposed laterally spaced wings 38 that are slidably received in the guideways defined by the housing portion 13.

The locking slide 4 is enlarged at one end yand formed to provide a recess 39 therein for reception of the last link of the chain 2, which is securely held in place by a rivet 40 extending through the recess 39. The locking slide 4 is cross-sectionally generally rectangular in outline to slidably fit the passage 16, and at its opposite end is formed to provide an elongated tongue portion 41 of a thickness to pass freely between the rear end 37 of the latch bolt 23 and the rear Wall of the housing 5, when the locking slide 4 is inserted upwardly in the passage 16, see FIG. 5. Longitudinally inwardly of the tongue portion 41, the slide 4 is formed to provide a cam surface 42 that engages the rear latch bolt end 37 to move the latch bolt 23 forwardly against bias of the spring 36. At the opposite sides of the tongue portion 41 and cam surface 42, the slide 4 is provided with flanges 43 having tapering end portions 44, the flanges 43 aiding in aligning the locking slide 4 with the passage 16 and guiding the tongue portion 41 toward the rear wall 15, so that the tongue portion 41 passes between the wall 15 and rear end 37 of the latch bolt 23. Intermediate the cam surface 42 and the enlarged end thereof, the locking slide 4 is formed to provide a latch bolt receiving cavity 45. The enlarged end of the locking slide 4 defines a shoulder 46 which engages the bottom wall 21 of the front body portion 13 to limit inward movement of the locking slide 4 through the passage 16, the arrangement being such that the latch bolt rear end 37 is received in the cavity 45 just prior to engagement of the shoulder 46 with the bottom wall 21, as shown in FIG. 4. The longitudinal dimension of the tongue portion 41 is such that the tongue portion 41 completely covers the opening in the rear wall 15, during inward movement of the locking slide 4 into the passage 16, prior to engagement of the latch bolt rear end portion 37 by the cam surface 42, as shown in FIG. 5. With this arrangement, the locking slide 4 moves smoothly past the opening 20 before rearward bias is imparted to the locking slide 4 by spring pressure on the latch bolt 23. This arrangement eliminates the necessity of a filler block or plate in the opening 20 to insure smooth and uninterrupted travel of the locking slide 4 upwardly in the passage 16. It Will be noted, with reference to PIG. 4, that, when the llocking slide 4 is fully received in the passage 16 and locked therein, the mounting screws 18 are fully covered by the locking slide 4, so that the housing cannot be removed' from the wall with the locking slide 4 in place. When it is desired to remove the locking slide 4 from the housing 5, it is only necessary to rotate the cylinder lock 25 to retract the latch bolt 23 from the cavity 45, whereupon the locking slide 4 will drop from the passage 16 under the action of gravity.

When it is desired to remove the lock 25 from the housing 5, the housing 5 is removed from the door frame 7, after which a small screw driver or the like may be inserted through the opening 20 into the recess 19 to move the retaining washer 33 into concentric relationship with the cylinder lock 25, permitting axial movement of the lock 25 upwardly from the bore 24.

While I have shown and described a commercial embodiment of my irnproved door chain lock, it will be understood that the same is capable of modification, without departure from the spirit and scope of the invention, as defined in the clai'ms. v

What is claimed is:

1. A door chain lock including a chain fastening means for securing said chain to a door and a door frame to permit limited opening of the door, one of said fastening means comprising:

(a) a housing having a rear wall for mounting against one of said door and door frame, and defining 'a longitudinal passage therethrough generally parallel to said rear wall and a transverse recess intersecting said passage substantially normal thereto and including an opening extending through said rear wall of substantially the same transverse dimensions as said recess,

(b) lock mechanism including -a key operated lock and a latch bolt, said latch 'bolt being mounted in said recess for movements toward and away from said `rear wall and having a rear end normally disposed in said passage in forwardly spaced relation to said opening,

(c) yielding means urging said latch bolt toward said Arear Wall,

(d) a lock retainer element engaging said lock within said recess and freely accessible through said opening for movement in a direction to permit removal of said lock from the housing,

(e) and an elongated locking slide having onel of its opposite ends secured to said chain, said locking slide being movable longitudinally into and out of said passage, and including:

( 1) a longitudinally extending tongue at its other end for movement longitudinally in the passage between said rear end of the latch bolt and said opening,

(2) a latch bolt engaging cam surface longitudinally inwardly of said tongue,

l(El) and a latch bolt re'ceiving cavity between said cam surface and the chain mounted end of the locking slide, said tongue 'being of such length relative to the dimension of said opening in a diirection longitudinally of the passage, that the tongue covers said opening prior to .engagement of said latch bolt by said cam surface responsive to said inward movement of said locking slide in said passage.

2. The door chain lock defined in claim 1, in which said looking slide includes a pair of laterally spaced guide fianges on said tongue and engaging a side wall of said passage to dispose said tongue rearwardly of the rear end of said latch bolt during 'said inward movement of the looking slide.

3. The door chain lock defined in claim 2, in which said tongue is of a thickness less than the normal distance between the rear end of said latch bolt and said opening, whereby to permit unrestricted movernent of said tongue past said opening.

4. 'The door chain lock de'fined in claim 2, in which said housing includes a pair of spaced fianges in said recess, said housing and flanges defining opposed guideways for said latch 'bolt, 'said latch `bolt having a pair of opposed laterally spaced Wings slidably received in said guideways.

References Cited UNITED STATES PATENTS 1,761,092 6/1930 Shinn 70-368 1,930,`975 10/1933 Jacobi 70-368 1,979,095 10/1934 Brauning 70-368 3,161,035' 12/1964 Adame et al. 70-93 MARVIN A. CHAMPION, Primary Examner.

ROBERT L. WOLFE, Assistant Examiner. 

